Detection of Adaptive Genetic Diversity in Wild Potato Populations and Its Implications in Conservation of Potato Germplasm

A better understanding on how genetic diversity is structured at natural habitats can be helpful for exploration and acquisition of plant germplasm. Historically, studies have relied on DNA markers to elucidate potato genetic diversity. Current advances in genomics are broadening applications allowing the identification of markers linked to genomic regions under selection. Those markers, known as adaptive markers, unlock additional ways to value and organize germplasm diversity. For example, conservation priorities could be given to germplasm units containing markers associated to unique geographic identity, and/or linked to traits of tolerance to abiotic stresses. This study investigated if adaptive marker loci were possible to be identified in a large AFLP marker dataset of ninety-four populations of the wild potato species S. fendleri. These populations originated from six different mountain ranges in southern Arizona, USA. A total of 2094 polymorphic AFLP markers were used to conduct genetic diversity analyses of populations and mountain ranges. Adaptive markers were detected using Bayesian methods which distinguished marker loci departing significantly from frequencies expected under neutral models of genetic differentiation. This identified 16 AFLP loci that were considered to be adaptive. To contrast diversity parameters generated with each set of markers, analyses that included all the 2094 AFLP markers, and only the 16 adaptive markers were conducted. The results showed that both were efficient for establishing genetic associations among populations and mountain ranges. However, adaptive markers were better on revealing geographic patterns and identity which would suggest these markers were linked to selection at the natural sites. An additional test to determine if adaptive markers associated to climate variables found two loci associated to specific climate variables in populations from different regions but sharing similar environmental structure. The distribution of adaptive markers among populations revealed that only two were needed to build a core subset able to keep all the markers. This preliminary assessment shows that adaptive genetic diversity could offer an additional way to measure diversity in potato germplasm and to set up options for conservation and research.

Screening for Aphid Incidence on Some Potato Germplasm in Plains of West Bengal

A field trial was conducted to study the impact of various potato germplasm against aphids, Myzus persicae (Sulzer) and Aphis gossypii Glover (Aphididae: Hemiptera) during rabi season from November to March in 2012-2013 and 2013-2014, respectively at Adisaptagram Block Seed Farm, Hooghly, West Bengal. The population of aphids was started on potato crop in between third week of December and first week of January irrespective of various germplasms, except K. Chipsona-2, where its infestation was initiated during second and third week of January. Then, their population was gradually increased to reach its critical level (ETL) during first and second week of January in most of the potato germplasm, except in K. Anand, K. Chipsona-1, K. Chipsona-2 and Sailaja, where it was crossed in between fourth week of January and first week of February. The peak population of aphids was observed during third and fourth week of February in most of the potato germplasm. It was observed that K. Ashoka, K. Badshah, K. Chandramukhi, K. Jawahar, K. Jyoti and K. Pukhraj were highly susceptible to the pests, while K. Anand and K. Sutlez were moderately susceptible but K. Chipsona-1 , K. Chipsona-2 and K. Sailaja were less susceptible or tolerant to the pests. Maximum tuber yield (t/ha) of potato was recorded in K. Badshah (36.58 - 43.92) while it was lowest in K. Chandramukhi (22.08 - 22.12).

Genetic diversity and population structure of 288 potato(Solanum tuberosum L.) germplasms revealed by SSR and AFLP markers

Potato(Solanum tuberosum L.)is an important staple food and economic crop in many countries.China has led world potato production in recent years.To understand the genetic diversity of potato germplasms and to enrich the current gene pool for potato improvement,we made a global collection consisted of 288 potato germplasms from eight countries and the International Potato Center(CIP).Using SSR and AFLP techniques,we evaluated the genetic diversity and population structure of these 288 potato accessions.A total of 190 alleles on 20 SSR loci were detected and all of the SSR alleles were polymorphic among these potato germplasms with an average of 9.5 alleles per SSR locus ranging from 2 to 23.The effective number of alleles per locus(Ne*),Nei’s genetic diversity(H*),and Shannon’s information index(I*)was from(0.1709±0.3698)to(1.6166±0.3414),(0.076±0.1388)to(0.3812±0.1886),and(0.1324±0.1970)to(0.5347±0.1440),respectively,and the mean polymorphic information content(PIC)value was 0.7312.A total of 988 AFLP alleles were detected by10 AFLP primer combinations with 983 polymorphic alleles,and 99.49%alleles was polymorphic with an average of 98.3polymorphic alleles per primer combination ranging from 91 to 116.The values of Ne*,H*and I*were from(1.5162±0.311)to(1.6423±0.3278),(0.3114±0.145)to(0.3675±0.1121),and(0.4761±0.1792)to(0.547±0.1322),respectively,and the average PIC value was 0.9871.Bayesian analysis discriminated the accessions into seven subgroup and an admix group.The majority of accessions from CIP and China were assigned into SG1,SG5,SG6,SG7 and admix group.Accessions in SG3 were mainly from CIP and two small groups SG2 and SG4 were mainly from northeastern China.In general,the results obtained from Bayesian statistical analysis,cluster analysis and principal coordinate analysis consistently revealed the lack of geographical differentiation among country-wide collections,indicating germplasm introduction was common for the countries out of potato origin center.The polymorphic markers and the differentiate genetic lineages found in this study provide useful information for potato improvement and conservation programs.

甘薯抗茎腐病鉴定技术的建立及种质资源抗性分析

为优化甘薯种质抗茎腐病鉴定技术,通过分析不同的接种方法和菌液浓度对甘薯种质抗性的影响,建立甘薯抗茎腐病鉴定标准,为甘薯抗病育种奠定基础。利用组培瓶蛭石薯苗擦伤接菌法和最佳接种菌液浓度(1.1×10^(7)CFU·mL^(-1)),对最具代表性的6个甘薯品种进行接种鉴定,并与田间抗性品种比较进行验证,室内接种抗性鉴定结果与田间抗性表现基本一致,表明新抗性鉴定技术的鉴定结果具有准确性、可靠性。进一步对65个甘薯材料进行抗病鉴定,发现绝大部分材料表现为感病或中感,7份种质(YD7002、DY7082-1、浙紫薯1号、TF1118、DY7032、南薯88和浙紫薯4号)对甘薯茎腐病具有稳定抗性。文章建立了甘薯抗茎腐病的新鉴定技术,鉴定和筛选出对甘薯茎腐病表现稳定抗性的种质,为甘薯抗茎腐病育种提供重要的种质资源,对于甘薯病害防控具有重要意义。

甘薯骨干亲本南瑞苕的利用与研究进展

南瑞苕是从美国引进的优良甘薯品种,也是我国甘薯育种上的骨干种质材料,具有显著的经济效益。收集、整理有关南瑞苕的研究报道和数据,综述南瑞苕的种质研究与引种表现、其后代及衍生品种选育、分子标记及遗传多样性分析、遗传转化等育种利用,组织培养与脱毒技术、块根的发育、代谢及产量、抗氧化特性等栽培生理,茎蔓顶部越冬做种技术、压蔓平栽、施肥与栽插等栽培技术,线虫、黑斑病、病毒病、干旱抗逆性等方面的研究进展;从南瑞苕优良基因的发掘和利用、南瑞苕产量和品质的形成机理和调控因素等方面展望其研究方向。

基于表型性状分析构建冀北地区马铃薯核心种质

为合理利用和更好保存马铃薯种质资源,本研究以冀北地区保存的502份马铃薯种质资源为材料,调查了26个表型性状,以不同块茎肉色进行分组,设置简单比例、对数比例、平方根比例和多样性比例4种取样方法,5%、10%、15%、20%、25%和30%共6种取样比例,利用2种遗传距离(欧氏距离和马氏距离)和4种聚类方法(类平均法、最长距离法、最短距离法、离差平方和法),探讨最佳取样策略,抽选核心种质。利用遗传多样性特征值、t检验、评价参数和系统聚类等方法对核心种质的表型性状进行评价,以及利用主成分分析对核心种质进行确认。结果表明,平方根比例法能够使核心种质更具代表性,20%为最佳取样比例,欧氏距离优于马氏距离,最优聚类方法为最短距离法,最终抽提出100份马铃薯核心种质,占全部种质的19.92%;核心种质的评价和主成份分析结果表明100份核心种质消除了大部分遗传冗余,保留了所有样本的遗传多样性,具有良好的代表性。本研究为马铃薯种质资源的有效利用和种质创新提供了重要的理论依据和实践基础。

基于DUS测试性状的冀北地区马铃薯品种遗传多样性分析

本研究通过马铃薯DUS测试性状,对适合在冀北地区种植的39个马铃薯品种展开遗传多样性分析以及性状的表型分析。结果表明,共检测到44个DUS测试性状的209个等位变异,平均每个性状检测到4.75个。多样性指数大于1的性状有34个,包括30个数量性状和4个假质量性状。多样性指数小于1的性状有10个,包括6个数量性状、2个假质量性状和2个质量性状。相关性分析表明,块茎表皮颜色,芽眼基部颜色与复叶主脉上表面花青甙显色强度高度相关。聚类分析将39个品种分成3组,每个组群具有各自独特的表型特征,各组特征性状与DUS测试指南指导分组性状一致。研究表明,DUS测试性状数量多,多样性也较高,可对马铃薯品种资源进行较为全面的客观评价。

马铃薯疮痂病抗病种质资源评价筛选

马铃薯疮痂病(Streptomyces scabies)近年在中国北方一作区、西南混作区、中原二季作区普遍发生,选育抗病品种是最有效、经济的防治方法。试验筛选对疮痂病具有抗性的马铃薯品种(系)材料。2022年利用自然病圃法对31个马铃薯品种(系)材料的疮痂病抗性进行评价鉴定并测定产量,2023年对筛选出的12份材料重复鉴定。2022年参试的31份品种(系)材料中,‘希森5号’‘Z496’‘Z740’‘Z759’‘Z760’‘Z812’‘Z917’‘Z962’‘Z1148’‘Z1152’‘Z1356’11份品种(系)材料具有疮痂病抗性,产量表现优异。2023年进一步测试鉴定结果表明,‘Z962’连续两年抗性鉴定结果为抗病材料(R),产量与当地主栽品种‘尤金’无显著差异;‘Z1148’‘Z1152’‘Z1356’‘Z740’‘Z760’‘Z917’产量高于对照品种,但仅‘Z740’产量与对照差异显著,对马铃薯疮痂病具有中等抗性(MR)。‘希森5号’和‘Z496’对疮痂病具有较强抗性,可作为杂交亲本材料进行疮痂病抗病育种创制杂交组合。研究筛选评价了31份马铃薯材料疮痂病抗性,为疮痂病抗病育种和病害防控提供基础材料。

Occurrence and molecular characterization of Potato spindle tuber viroid(PSTVd) isolates from potato plants in North China

China is the largest potato producing country worldwide,with this crop representing the fourth largest staple food crop in China.However,the steady presence of Potato spindle tuber viroid(PSTVd) over the past five decades has a significant economic impact on potato production.To determine why PSTVd control measures have been ineffective in China,more than 1 000 seed potatoes collected between 2009 and 2014 were subjected to PSTVd detection at the Supervision and Testing Center for Virus-free Seed Potatoes Quality,Ministry of Agriculture,China.A high PSTVd infection rate(6.5%) was detected among these commercial seed potatoes.Some breeding lines of potato collected from 2012 to 2015 were also tested for PSTVd infection,revealing a high rate of PSTVd contamination in these potato propagation materials.Furthermore,comparison of the full-length sequences of 71 different Chinese PSTVd isolates revealed a total of 74 predominant PSTVd variants,which represented 42 different sequence variants of PSTVd.Comparative sequence analysis revealed 30 novel PSTVd sequence variants specific to China.Comprehensive phylogenetic analysis uncovered a close relationship between the Chinese PSTVd sequence variants and those isolated from Russia.It is worth noting that three intermediate strains and six mild strains were identified among these variants.These results have important implications for explaining the ineffective control of PSTVd in China and thus could serve as a basic reference for designing more effective measures to eliminate PSTVd from China in the future.

加工型马铃薯种质资源的评价与筛选

为了创制优异的加工型马铃薯基因型和新品种,试验对98份马铃薯种质的块茎品质(淀粉、还原糖含量)进行检测,鉴定筛选出20份高淀粉(淀粉含量≥18.0%)种质材料,39份低还原糖(还原糖含量≤0.20%)种质材料。根据种质的亲缘关系和主要特性进行杂交亲本的选配,配制“高淀粉×低还原糖”类型的杂交亲本组合,筛选出后代F1单株表现优异的炸片高淀粉加工型组合“天薯10号×克新17号”。对组合“天薯10号×克新17号”后代239份F1群体的淀粉含量、还原糖含量和炸片色泽进行检测与分析,鉴定筛选出一批具有优良基因型的马铃薯种质材料:83份基因型淀粉含量≥18.0%,56份基因型还原糖含量≤0.20%,85份基因型炸片色泽值≤3.0。这些优异的基因型可作为高淀粉和低还原糖马铃薯品种选育的亲本材料。

195份马铃薯种质资源表型性状综合评价

为研究马铃薯种质资源表型性状的遗传多样性,以冀西北地区收集的195份马铃薯种质为材料,利用Shannon-weaver多样性指数、变异系数、相关性分析等进行遗传多样性分析和综合评价。结果表明,16个描述型性状共有62个变异类型,遗传多样性指数变幅为0.69~1.73,其中株型、芽眼深浅、块茎整齐度、薯肉色、薯皮色和薯形的遗传多样性程度较高。6个数值型性状中单株结薯数变异系数较大(41.30%),茎粗变异系数较小(15.71%);遗传多样性指数变幅为1.89~2.07,其中株高、茎粗、平均单薯重、块茎产量遗传多样性指数较高。对195份参试种质的综合得分C值采用离差平方和法进行聚类,主要划分为4个类群,各类群表型性状差异明显。根据聚类分析、种质高产稳定性和鲜食马铃薯生物学指标的评价结果,筛选出9份优异种质,可作为冀西北地区鲜食马铃薯杂交育种亲本或中间材料。本研究筛选出的优异性状马铃薯种质,为冀西北地区马铃薯种质资源创新、充分利用提供了理论依据和材料基础。

马铃薯种质演化与分类研究进展

马铃薯野生种具有丰富的遗传变异,是栽培马铃薯遗传改良的重要优良性状来源。然而,关于野生和栽培马铃薯的分类长期以来一直存在争议。1990年Hawkes将Petota组划分为21个分类系,其中包含7个栽培种和228个野生种。随着分子生物学和测序技术的发展,2014年Spooner等对马铃薯分类进行整合和补充,基于各种形态学和分子证据,最终将Petota组划分为由107个野生种和4个栽培种组成的3个进化枝。此外,考古学和现代基因组学分析证实了S.candolleanum是栽培马铃薯的直接祖先种。随着近年来大量的马铃薯种质被测序,更多的基因组信息被揭示,结合新兴的基因组选择育种、基因编辑等技术,有望创新马铃薯育种模式与机制,为马铃薯精准分子育种提供新思路。综述探究了马铃薯种质演化、分类进展以及利用展望,以期为马铃薯种质资源改良和育种利用提供参考。

马铃薯种质资源的耐碱性评价和耐碱种质离体筛选

本试验以前期从1000余份马铃薯种质中筛选出的12份耐盐马铃薯种质和10份盐敏感种质为材料,在0、5、10、15、20 mmol/L NaHCO_(3)胁迫下,测定植株有效生长率,并建立NaHCO_(3)浓度与植株有效生长率的回归方程。结果表明,根据回归方程计算植株有效生长率达到50%时的NaHCO_(3)浓度为11.60 mmol/L,因此确定11.60 mmol/L NaHCO_(3)为筛选马铃薯耐盐碱种质的适宜碱浓度。在11.60 mmol/L NaHCO_(3)浓度下,测定供试材料植株的有效生长率、株高、根数、茎叶重和根重,计算这些指标的耐碱系数,并根据指标值和耐碱系数对供试材料的耐碱性进行综合评价,筛选出2份耐碱种质B154和D56。高耐碱性鉴定表明,B154和D56对20 mmol/L NaHCO_(3)胁迫有较强的适应性,茎叶重分别为对照的34.48%和14.56%,根重分别为对照的31.25%和9.33%,株高分别为对照的64.77%和48.90%。

利用分子标记筛选马铃薯抗孢囊线虫资源

马铃薯孢囊线虫(PCN,potato cyst nematode)是马铃薯中重要的检疫性病害,可造成马铃薯减产80%。近年来,据报道西南地区多个马铃薯主产区发现马铃薯金线虫(Globodera rostochiensis)。为了我国马铃薯生产安全,筛选马铃薯孢囊抗性种质资源、选育抗性品种迫在眉睫。本研究利用前人报道的抗性分子标记N146、N195、57R、TG689、Gro1-4-1和Gpa2-2,对云南省农业科学院保存的875份马铃薯种质资源进行马铃薯孢囊线虫抗性标记筛选。筛选到211份资源含有马铃薯金线虫抗性基因H1分子标记(N146、N195、57R和TG689),其中114份资源中同时含有4个分子标记;7份资源含有马铃薯金线虫抗性基因Gro1-4分子标记Gro1-4-1;237份资源中含有马铃薯白线虫抗性基因Gpa2分子标记Gpa2-2。本研究结果将为马铃薯孢囊线虫抗性育种提供技术支撑和材料基础。

延长马铃薯种质资源低温保存条件的探究

试管苗离体保存是马铃薯目前应用最广泛的种质资源保存方法,探究延长试管苗继代周期的保存条件可以有效减少风险并降低保存成本。从实验室种质资源库中挑选了6个不同基因型的马铃薯材料,以植株状态、株高和存活率作为指标,探究不同预生根处理、保存温度、培养基蔗糖浓度和继代方式对马铃薯试管苗保存的影响,以探索广泛适用于马铃薯试管苗长期低温保存的条件。不进行预生根处理的试管苗在低温保存的第60d几乎不生长,随后死亡,说明预生根处理是试管苗低温保存的必要条件。4℃条件下试管苗的生长比7℃更缓慢,在第90d时的株高明显更小,4个材料的试管苗存活率仅为53.75%,而7℃条件下存活率为100%,说明7℃更适于不同基因型马铃薯种质资源的低温保存。8%蔗糖浓度培养基中的试管苗在第90d时的株高明显低于4%蔗糖浓度,存活率统计显示4%蔗糖浓度培养基中的试管苗在7℃保存第270d时全部死亡,8%蔗糖浓度培养基中的试管苗存活率达到61.25%,表明8%蔗糖浓度能明显延长马铃薯试管苗的低温保存时间。由此可见,可以采用8%蔗糖浓度培养基和7℃环境温度用于大部分马铃薯株系的长期低温保存。此外,探究了一种试管苗-组培盒苗交替继代培养的方法,能有效改善长势弱的种质资源的保存,将这些材料在低温保存第90 d的存活率从直接继代试管苗22.50%提高到试管苗-组培盒苗交替继代95.00%。此研究对优化马铃薯种质资源的长期保存条件具有重要的指导作用。

利用早代定向筛选与联合鉴定技术选育专用型甘薯品种的研究

为了提高专用型甘薯品种选育的效率,满足多元化消费市场的实时需求,本文结合研究团队近年来的育种实践经验,探索了利用早代定向筛选与联合鉴定技术选育专用型甘薯品种的方法。首先依据品质相关农艺性状对种质资源进行分类,充分利用中间亲本的轮回改良策略加快品质相关基因资源的聚合速度,利用分子标记辅助选择与品质性状精细鉴定相结合的方法,完成高花色苷、高胡萝卜素等鲜食专用型株系的筛选,实现杂交子代早代的精准鉴定。在种质资源鉴定与利用的基础上,将传统“五圃”选育法中的复选圃、鉴定圃、高鉴圃环节整合为联合鉴定圃,将鲜薯的增产、稳产潜力以及抗性的考察整合到联合鉴定圃与品比圃鉴定环节完成,从而在4~5年时间内完成杂交子代的精准鉴定,极大地提高育种效率。育种实践证明,改良后的技术对品质相关性状的遗传改良切实可行。随着关键农艺性状相关有效分子标记的开发,该育种技术将拥有更为广阔的应用前景。

195份马铃薯种质资源表型性状综合评价

搜集、整理、鉴定马铃薯种质资源并保存、归类,有效建立马铃薯数据库管理系统,构建应用管理平台,实现马铃薯种质资源的充分共享和可持续性利用,对于促进和发展马铃薯育种意义重大。种质资源是新品种选育的物质基础,文章对山西农业大学高寒区作物所马铃薯课题组搜集保存的195份马铃薯种质资源进行大田种植观察,以期充分了解种质资源的品质特性,挖掘种质资源的利用价值,有利于提高育种效率,对选育不同功能用途的优质品种具有重要意义。

薯圆加工专用型甘薯种质资源筛选及工艺优化

随着人们生活水平提高,消费观念转变,以甘薯为主要原料的薯圆,越来越受到年轻人的喜欢。以筛选适合薯圆加工专用型甘薯种质资源和研究薯圆加工专用型甘薯的最佳工艺配方为目的,采用福建农林大学洋中科教基地种植的145份甘薯种质为原料进行薯圆加工,根据感官综合评分,筛选出适合薯圆加工的专用型甘薯种质,并对筛选到的种质开展工艺优化正交试验。结果表明:从145份甘薯种质资源中筛选出薯圆加工感官评价分数大于80分的甘薯种质5份,分别为SP1、SP4、SP35、SP70、SP87,以得分较高的SP1开展薯圆最佳工艺研究,其最佳工艺配方为木薯粉20 g、水6 mL、甜叶菊0.10 g。

我国甘薯种质资源研究的历史与现状

甘薯种质资源是国家的宝贵财富,也是育种工作的物质基础。为了防止资源的流失,我国在1952～1958年和1979～1982年分别进行了两次全国性甘薯资源的收集工作;在此基础上,在国家统一规划下于1990年和1996年分别建立了"国家种质广州甘薯圃"和"国家种质徐州甘薯试管苗库",主要负责全国甘薯品种资源的收集、保存、整理与分发利用等工作。通过资源鉴定和评价研究,筛选出一批包括抗病性强、适应性广和品质优良的种质资源,有效地促进了我国甘薯品种改良和资源创新的研究,并成为我国重要的甘薯种质资源交换中心。

马铃薯品种遗传多样性分析

为解析一套(559份)从世界各国收集的马铃薯种质资源的遗传多样性,用16个表型性状和36个SSR标记进行了聚类和多样性参数分析。对454份表型数据完整材料的UPGMA聚类分析表明,在欧氏距离14.66处被聚成2个类群(A_1和A),其中A_1在欧氏距离12.74处被分为A_(11)和A_(12)亚群;454份材料在欧氏距离11.73处被划成9个类群,包括4个小类(A、B、C和H)和5个大类(D、E、F、G和I),其中类群I所包括的材料占总数的57.5%,该结果较好地揭示了马铃薯种质材料之间的形态差异,区分生态类型不同和遗传差异明显的亲本。36个SSR标记在559份材料中共检测出134个多态性位点,每对引物检测1~7个等位变异,平均3.72个,引物多态性信息量(PIC)为0.1545~0.7743,平均为0.5783,说明品种间有丰富的遗传多样性。NJ系统进化树分析表明,559份材料可分为3个大群。类群I为一个混合群,各地区品种均有分布,包括133份马铃薯材料,占总数的23.8%;类群II中欧洲、北美及中国东北和西北地区的材料所占比重较大,数量为187,占33.5%;类群III中北美、南美以及中国东北和西南地区马铃薯材料所占比重较大,包含239份材料,占42.8%。表型性状聚类与SSR分子标记聚类结果相似,均与地理位置有很大相关性,应结合共同用于评价马铃薯品种遗传多样性。